冻融循环对混凝土梁抗弯性能的影响

冻融作用是影响钢筋混凝土结构耐久性的主要原因之一，通过对快速冻融试验后试验梁的纯弯试验，研究了梁截面混凝土应变、挠度开展情况及承载力的变化规律。屈服荷载和极限荷载随着冻融循环次数的增加而降低；相同荷载下梁的挠度也明显增大，梁的刚度逐渐减小。结合快速冻融试验结果，基于已有冻融循环作用下混凝土梁抗弯承载力计算模型的分析，选择了合理的抗弯承载力计算公式进行计算分析，试验值与计算值基本吻合，为多因素影响下梁承载力损伤模型的建立奠定了基础。

EFFECTS OF FREEZE-THAW CYCLES ON FLEXURAL PERFORMANCE OF CONCRETE BEAMS

Freeze-thaw cycles are one of the main reasons affecting the durability of reinforced concrete structure. By pure bending test after fast freezing-thawing cycles, the concrete strain variation, the deflection development and the bearing capacity were studied. The yield load and ultimate load decreases with the increase of freeze-thaw cycles. Under the same load, beam deflection increases and the beam stiffness decreases. With quickly freeze-thaw test re- sults, flexural bearing capacity calculation model under the freeze-thaw cycles was analyzed. The reasonable for- mula was chosen for calculating flexural bearing capacity. The calculated values agree with the test value. It is the foundation for studying the beam damage affected by multi factors.